If I am designing my axle for a worse case scenario, I need to take this possible axial load into account? My initial thought that was when the user is going around a corner, a lot of the users weights and the weight of the wheelchair frame will be transfers down the axle and this would be my...
I'm in the process of calculating my combined stress on an axle I am designing, I have calculated the bending and torsional stress, however I need to calculate the direct stress in the axle. In order to do this I need to know the axial thrust in my axle, I understand what axial force is but I am...
After looking over my calculations, I've realised I had my bending moment slightly too high, therefore my bending stress is wrong. My bending stress is actually 63MPa.
I took the rolling resistance from the below table taken from this link http://www.engineeringtoolbox.com/rolling-friction-resistance-d_1303.html
Perhaps a higher one is more suited for rough terrain?
Therefore, 75/3000=0.25
I want my answer to be 1.4 (walking speed), so I need to decrease...
Ah yes, I forgot to convert to MPa.
I am familiar with deflection however not sure how to calculate it under these parameters, could you give me some pointers?
Thanks, I will do. Now that I have this bending stress for a 20mm diameter shaft, how do I decide if this is suitable for my application?
Or do we now look at torsional stress?
What kind of information would be required to take rough terrain in account?
Can you clarify why this would be at 0.25 m/s? I thought I was calculating the output power, and my initial calculation had found the output to be too high at 300N?
1. Only the load shown in the previous diagram and this axle will be manually driven at low speeds.
2. Between 10mm and 23mm.
3. Preferably a stock bar sized would be used for the axle to keep costs down, so the closest one to the needed axle.
4. I am yet to select my bearings but only plan...
I've had a re-read through of the thread and answered most of my questions, thank you.
I initially did the calculations using a gear ratio of 0.2m diameter for the driven and 0.1m diameter for the driver. I worked it out as getting an output of Fv=301.7N with the method you have shown. Looking...
Thanks for your help, I'll look into this ASAP.
Regarding axial thrust, is there a way to determine what this load is for my circumstance? I understand it may not be a formula, just what factors I need to consider.
Thanks a lot for your help, I have a few questions regarding this method.
1. Am I correct in thinking I determine my own gear ratios to begin with and carry out the equations, deciding if my end result is correct and changing the ratio accordingly if required?
2. For calculating hand velocity...
This is what the initial post was about, although now I'm unsure exactly where I've been helped with this due to the multiple different ideas from different users (I understand that's the point of a forum).
Are you able to clarify how I go about calculating this? Not taking into account any...
Is there even a point in me having two gears then? Besides from locating the lever arm away from wheel axle?
It seems that I am not getting any mechanical advantage at all from having two gears.
Are the equations shown here https://theconstructor.org/structural-engg/solid-mechanics/combined-bending-direct-and-torsional-stresses/3704/ what I need to use to do this?
I've calculated my bending stress as 50.4 and my torsional stress as 10.2 using the method shown in that linked page. I'm...
I am just trying to work out what the size of each gear should be for a use over mainly rough terrain. Is this possible? Or will the gears just be the same size with the power provided to the wheels being varied by where the user pushes the lever?
I'm currently in the process of designing a bearing housing for an axle. Unfortunately I am not 100% on the diameter of my axle yet but I want to have a clear understanding what tolerances to use on my axle to bearing bore and bearing outer diameter to the bearing housing.
I've looked over the...
Hopefully the above diagram helps. I have calculated my reactions as 1.099kN on the left bearing and -0.0314kN on the right bearing. Giving me a bending moment of 0.063.
This over the tensile strength of steel (274 mPa) is 0.00023.
So I believe this to be my plastic modulas? (Sx) and I am...
Hi,
Really need some help with figuring out the max bending moment in the diagram shown below (I'm aware this is extremely simple but time and stress appear to have the better of me, so any help is appreciated)
I think I've worked out the reactions at each support by doing m=wL as the...
The front two wheels are bicycle wheels of about 660mm diameter and then a rear castor wheel which is about half the size which allows the wheelchair to steer.